The Department of Veterans Affairs will cover the costs of service dogs to help veterans with impaired vision, hearing or mobility, but will not cover canines assigned for mental disabilities, according to regulations published on Wednesday in the Federal Register.

The VA said that despite many individual veterans’ testimonials that mental health service dogs provide relief from the symptoms of combat-related disabilities such as Post Traumatic Stress Disorder (PTSD), it lacked research substantiating the efficacy of mental health service dogs.

"VA has not yet been able to determine that these dogs provide a medical benefit to veterans with mental illness," the department said. "Until such a determination can be made, VA cannot justify providing benefits for mental health service dogs."

To be defined as a "service dog" the animal has to be trained to do specific tasks for a person — such as picking things up, guiding them or providing balance.

Trainers say that for veterans suffering mental disabilities such as PTSD or Traumatic Brain Injury (TBI), dogs can be trained to help avert panic attacks and wake them up as they enter a nightmare. The animals can be taught to remind veterans to take medications and alert them if they have left a burner lit on the stove.